Questions

No. The sheets tell you which square gets which color and how tall to stack it, and that really is all there is to it. You will pick up the rest as you go along.

Honestly, we do not know. We are aiming to finish inside one semester, but a lot depends on how many people turn up.

The 18 baseplates do not all come out at once. We roll them out a few at a time, along with the sheets that go with them, which keeps the table manageable and leaves a clear next thing to pick up. Expect a new batch about once a week, though we will speed that up or slow it down to match how fast the building is actually going. If it races ahead we will put more out, and if it slows down we will wait.

There are also two passes over the whole board. Phase 1 builds the terrain in grays, and it is a finished thing in its own right once it is done. Phase 2 comes afterwards and lays the geology colors on top. Even if you miss all of Phase 1, there is a second chance at the same square later.

Come whenever suits you. There is no session you need to be at and nothing to sign up for. Drop in for 5 minutes or stay the afternoon.

Yes of course! It's just LEGO after all. Pull it off and put the right one on.

The same goes if you spot something wrong that somebody else built. If it looks easy to fix, please go ahead, and if it does not, come and let us know.

It goes on display. The 18 baseplates do not clip to one another, so the finished map will need a rigid board behind it to hold everything square.

Please do, we would love that. All the sheets, the brick counts and the element numbers are free to download, and the code that generated them is open too.

Every sheet, free to download →

18 baseplates is about what a table can hold and a budget can buy. Each one is 32 x 32 studs, which works out at 16 x 16 of our 2x2 squares, so 6 across and 3 down gives us a 96 x 48 grid, or 1.54 x 0.77 m of Mars.

A bigger board would give us a sharper map, but the cost climbs very quickly. Doubling the detail in both directions would need 4 times the bricks, 4 times the money and 4 times the table.

Real Mars runs from about −7.2 km at the bottom of Hellas up to nearly +20 km on top of Olympus Mons, which is a range of roughly 27 km. If you chop that into 2 km steps, the tallest stack comes out at 14 plates, or about 45 mm.

Starting the bottom plate at −8 km has a nice side effect too, because it puts 0 km, the height the rest of Mars is measured against, at exactly 5 plates up.

About $1,225 so far, against a $3,000 budget from the de Florez Fund.

The 12,000 gray and white plates came from BrickLink for around $690, and the colored ones from LEGO Pick a Brick. A whole planet costs less than one large LEGO set.

The finished model will weigh somewhere around 15 kg.

Mostly by what LEGO actually makes. If there is no 2x2 plate in a color then we cannot use it, and there are fewer of those than you might expect.

For Phase 1 the 3 elevation bands are Dark Bluish Gray, Light Bluish Gray and White. They are cheap in bulk, they are easy to tell apart even under bad lighting, and they cycle cleanly as the stacks climb.

For Phase 2 we should warn you that the colors look nothing like the real units. Mars is visually quite limited, mostly shades of rust and dust, so a true color map of it would be unreadable.

What we did instead was pick colors that are only reminiscent of what each unit is. Blue where water once sat or where ice still does, brown for the old highlands that cover most of the planet, dark red for the great impact basins. They are there for fun and to help you tell one square from the next. They are not an optical representation of the surface.

The Hammer projection, sometimes called Hammer-Aitoff. It squeezes the whole globe into an ellipse.

We picked it because it is equal-area. Since each square on the board is the same 2x2 plate, each one has to stand for the same amount of ground. If we had used something like Mercator, a plate near the pole would mean a tiny patch while a plate at the equator meant an enormous one, the brick counts would all be wrong, and the projection would never reach the poles at all.

The ellipse is also why the board has bare corners. Of the 4,608 squares in the 96 x 48 grid, 980 fall outside the map and stay empty, showing the dark baseplate underneath.

More on flattening a sphere →

Two published datasets, both free for anyone to download.

The heights come from MOLA, the Mars Orbiter Laser Altimeter. It flew on Mars Global Surveyor and bounced a laser off the planet through the late 1990s to measure its shape.

Smith, D. E. et al. (2001) Mars Orbiter Laser Altimeter: experiment summary after the first year of global mapping of Mars. Journal of Geophysical Research 106(E10), 23689–23722.

The colors come from the United States Geological Survey's geologic map of Mars, the standard modern map of what the surface is made of and how old it is.

Tanaka, K. L. et al. (2014) Geologic map of Mars. U.S. Geological Survey Scientific Investigations Map 3292.

The topography, in full →

The geology, in full →

The pack is generated by code and rebuilds from scratch in about a minute.

GMT, the Generic Mapping Tools, does the projection and bins the global grids down to 96 x 48 squares.

Python does the rest. It works out how many plates each square needs, counts the bricks and writes all the printed sheets, leaning on numpy and rasterio along the way.

Three.js draws the 3D model on this site.

The bricks themselves came from LEGO Pick a Brick and BrickLink.

Bigger, though by less than most people expect. Earth's diameter is 12,742 km against Mars at 6,779 km, which at the scale of this board gives

An Earth would sit next to our Mars on the same table, since the board is 1.54 m wide.

The comparison by area is closer. The whole surface of Mars comes to about 144 million km² and all the dry land on Earth to about 149 million km². Every desert, forest, mountain range and city you have been to would tile onto the board in front of you.

Everest is 8.85 km above sea level. Our plates are 2 km each.

The biggest mountain on Earth would come up to about the knee of the biggest one on Mars. And remember that on a board scaled honestly in both directions, Everest would stand 0.64 mm tall, so you would need a magnifying glass to find it.

Almost certainly not.

Olympus Mons is 22 km tall but roughly 600 km wide, so its flanks slope at about 5 degrees, which is gentler than a lot of roads. You could walk up it for days without ever feeling like you were climbing a mountain, and the summit would stay below the horizon the whole way.

The same holds for any tall stack on this table, which looks dramatic only because we stretched the model 22 times. Anyone standing on the real surface would find a gently sloping desert.

Because nothing has tidied it up. Earth has three great erasers, and Mars is missing all three.

No plate tectonics. On Earth the crust slides around, so a volcano drifts off its hot spot and dies young, which is why Hawaii is a chain of them. On Mars the crust sits still, so a single volcano can sit over the same plume for billions of years and simply keep growing.

Weaker gravity. Mars pulls at about 38 percent of Earth's, so a mountain can pile much higher before its own weight makes it slump.

Almost no erosion. There is no rain, nothing running today, and no ocean chewing at the coasts. Craters punched out nearly 4 billion years ago are still sitting there. On Earth they would have been rained flat, buried, or swallowed at a subduction zone long ago.

Pick a height on the board, and anything shorter than it is underwater. Guess how much of the planet drowns before opening the numbers.

The water pools in the north, in one connected sheet, because the northern third of Mars sits kilometers lower than the south. That step in elevation is the crustal dichotomy, and the board reproduces it from the heights alone.

Did it actually happen? That part is genuinely argued over. People have traced possible old shorelines around the northern plains for decades, and the higher, older one is called Arabia while the lower, younger one is called Deuteronilus.

The trouble is that an ocean surface has to be level, and those traced shorelines are not. They wander up and down by kilometers, which for a long time was the strongest argument that they were never coastlines. One answer, from 2018, is that Tharsis was still piling up while the shorelines were forming, and the weight of all that volcano bent the whole surface out of level afterwards.

Where would you put the shoreline? A single plate is 2 km of height and 222 km of ground, which puts a real shoreline far below what the board can resolve.